NMR Spectra of Flavone Di-C-glycosides from Apometzgeria pubescens and the Detection of Rotational Isomerism in 8-C-Hexosylflavones

Abstract

1 H and 13 C NMR spectra are documented for the novel flavone-6,8-di-C-glycosides isolated from the liverwort, Apometzgeria pubescens. The existence of rotational isomerism evident from these spectra is shown to be general for 8-C-monohexosylflavones and of possible diagnostic value.